mail headers query

[Anon]

$mail_headers="Content-Type: text/html; charset=iso-8859-1\n From:[e-mail]\n";

$subj="test";

Hi all
If I just use the HTML part of the header above theres no problem.
But if I use both I get the 'From' bit fine but I get all the raw html in the body of the message.

can someone help?

Cheers

Nick